1. Field of the Invention
This invention relates to a liquid crystal display, and more particularly to a liquid crystal display device and method of fabricating the same that reduces a reflectivity of an LCD display screen.
2. Description of the Related Art
Generally, a liquid crystal display (LCD) of an active matrix driving system uses thin film transistors (TFT's) as switching devices to display images. Since such LCD's can be made smaller than cathode ray tubes, they have been widely used as monitors for personal computers or notebook computers, as well as in office automation equipment, such as copy machines, etc. . . and in portable equipment, such as a cellular phones and pagers, etc.
Referring to FIGS. 1 and 2, in the conventional LCD device, a gate line 14 and a data line 13 is formed on a rear substrate 1 crossing each other, and a pixel electrode 10 is formed at the interior thereof. A TFT 12 is formed at an intersection between the gate line 14 and the data line 13.
The TFT 12 includes a gate electrode 3, a source electrode 6 and a drain electrode 7 to apply a data signal at the data line 13 to the pixel electrode 10 during an application of a scanning pulse to the gate electrode 3. The gate electrode 3 is connected to the gate line 14, while the source electrode 6 is connected to the data line 13. The drain electrode 7 is connected, via a contact hole 9, to the pixel electrode 10, which is deposited with a transparent conductive material such as indium-tin-oxide (ITO). A gate insulating film 4, deposited using an inorganic insulating material, is formed on the gate electrode 3 and the gate line 14, and an active layer 20 and an ohmic contact layer 5 are deposited thereon. A passivation layer 8 made from either an inorganic insulating material or an organic insulating material is formed on the TFT 12.
In the conventional LCD device, a storage capacitor 19 is provided on the gate line 14. The storage capacitor 19 accumulates a driving voltage (charge) of the next scanning line during the previous scanning period, to thereby lower the driving voltage. An upper electrode 15 of the storage capacitor 19 is made from a metal alloy upon formation of the source electrode 6 and the drain electrode 7, as shown in FIG. 3. The gate line 14 that overlaps the upper electrode 15 serves as a lower electrode of the storage capacitor 19. The upper electrode 15 of the storage capacitor 19 is connected, via a contact hole 16 passing through a passivation layer 8, to the pixel electrode 10.
A black matrix 11 is provided on a front substrate 2, which is opposed to the rear substrate 1, with a liquid crystal therebetween. The black matrix 11 is positioned at a portion other than an effective display area of a pixel to absorb all wavelengths of light incident thereon. Further, on the front substrate 2 there are provided a common electrode, a color filter and an alignment film (not shown) in addition to the black matrix 11.
Such an LCD device has a problem in that a large amount of reflective light is generated at the display screen due to a structure of the black matrix 11. More specifically, the black matrix 11 does not overlap with a pixel electrode side portion 17 of the drain electrode 7 and a pixel electrode side portion 18 of the upper electrode 15 of the storage capacitor, as shown in FIG. 1, due to its pattern structure. As a result, as shown in FIGS. 2 and 3, when external light is incident on areas O1 and O2 of the black matrix 11, the upper electrode 15 of the storage capacitor and on the drain electrode 7, it is reflected from the upper electrode 15 and the drain electrode 7, which are made of metal. Such a reflected light is incident on a user's eye, and reduces the contrast, thereby reducing quality of a displayed image. For instance, since an aircraft cockpit is exposed to direct sunlight, various LCD panels installed in the cockpit of the aircraft generate a large amount of reflected light. Therefore, the LCD panel in an aircraft may have a deterioration of picture clarity due to the reflected light, sometimes causing pilot error.